I have previously described a non-cytotoxic lymphokine (TMIF) that inhibits the migration of a variety of tumor cells in vitro. this lymphocyte-derived mediator is distinct from other migration inhibitory lymphokines that affect inflammatory cells. The purpose of the present proposal is to further characterize TMIF from a variety of in vitro and in vivo sources and to extend observations regarding cells capable of responding to it. Specifically, I will examine cultured tumor cell lines as well as tumors propogated in vivo in ascitic form. In addition, cells will be obtained from dissociated solid tumors and their capacity to respond to TMIF will be investigated. I will also continue to evaluate the specificity of TMIF for neoplastic cells. Additionally, I will attempt to obtain pure TMIF and antibody to it utilizing hybridoma techniques. The availability of such reagents, though not essential to the performance of the above studies, would allow for a more precise definition of the nature and properties of TMIF and would provide the necessary materials for the ultimate extension to an investigation of the in vivo effects of this mediator. This, in turn, could facilitate utilization of TMIF in clinical settings, either as a therapeutic modality of as the basis of an in vitro test that could provide information of prognostic significance.